The developing use of hydrogen as an energy carrier will require broad-based and flexible hydrogen supply systems to provide hydrogen efficiently to a large number of geographically-dispersed hydrogen consumers. The hydrogen supply infrastructure will be highly decentralized and will have many diverse users with a wide range of hydrogen requirements. Hydrogen may be generated at user sites for immediate consumption, stored for future use, or dispensed for mobile use. Alternatively, hydrogen may be generated at central production sites, transported to local sites, and stored at the local sites, where the stored hydrogen may be used, held for future onsite use, or dispensed for mobile use.
Numerous hydrogen applications are being developed, including hydrogen-powered fuel cell or internal combustion vehicles, stationary power applications, backup power units, power grid management, power for remote locations, and portable power applications in consumer electronics, business machinery, and recreational equipment. Hydrogen dispensing stations will be needed for vehicle refueling, and smaller refill centers will be needed for portable devices such as computers, mobile communication devices, and other electronic equipment.
Because the hydrogen volume requirements in these applications will vary significantly and because the diverse users will be geographically dispersed, the logistics of hydrogen supply under normal conditions will be complex but manageable. Under abnormal conditions, however, hydrogen supply logistics may be especially complex and unpredictable. Abnormal conditions would occur, for example, when onsite hydrogen generators malfunction or are shut down for maintenance, or alternatively when local hydrogen demand temporarily exceeds local supply capability or storage capacity.
There is a need for flexible and adaptable hydrogen supply methods to address these problems and supply hydrogen to growing energy-related markets for hydrogen. Embodiments of the present invention, which are described below and defined by the claims that follow, address this need and offer flexible hydrogen supply alternatives for varied user requirements under both normal and abnormal demand conditions.